It has become a common practice to flavour tea, herbs and tobacco in order to increase their attractiveness. In recent years, the growing demand for aromatized tea for instance is partly due to the attraction felt by the consumer for non-traditional tea-based drinks such as soluble tea, iced-tea, various liquid mixtures ready for consumption or carbonated drinks, which are on offer in various forms, in bottles, cans or cartons.
Traditionally, tea has been flavoured by adding certain essential oils, e.g. jasmin, rose or bergamot essence, or spices such as cinnamon, cardamom or mint or fruit flavours, e.g. strawberry, peach, banana or grape. On the other hand, tea acquires its characteristic aroma during the various stages of maturing and packaging. Withering and curling of leaves, fermentation and drying are other operations which modify the original taste and flavour of tea and which, like the nature of the soil and climatic conditions of the place where the plant is cultivated, determine its aromatic characteristics.
Although systematic studies have not been made, experience has shown that prolonged storage of tea leaves after fermentation destroys the aroma, and hence there is a need for flavouring.
Usually, flavouring is done simply by spraying the flavour in solution in an inert edible solvent onto the leaves, or by mixing the leaves with solid particles containing the flavouring, in which case the technique of micro-encapsulation of the "fluidised bed" process is employed [see e.g. European patent application 70719 published on Jan. 26, 1983]. However, these methods have serious disadvantages. Firstly, the method of spraying a solution of flavouring is inefficient in that the dispersed flavouring tends to evaporate from the surface of the treated leaves in a relatively short time, a disadvantage which has been addressed by U.S. Pat. No. 4,880,649 to Firmenich.
On the other hand, the method using solid flavoured capsules is inconvenient in operation since it has been found that the particles tend to separate by gravity from the mass of leaves and accumulate at the bottom of the vessel in which they are stored or transported. Besides, when tea leaves are flavoured by this latter method and the resulting product is intended to be used for the manufacture of tea bags, the added flavour granules separate from the leaves and tend to sift through the walls of the bags. In both cases, the flavouring is non-uniform.
The same sort of considerations applies to the flavouring of dry vegetable matter other than tea, for instance cut tobacco and minced vegetables, herbs and spices. In all these products, granules of flavour tend to separate from the vegetable particles and hence render the packaging of the flavoured material subject to lack of uniformity.
Micro-encapsulated flavours are extensively used in the food industry. Their preparation is widely known [see e.g. L. L. Balassa and G. O. Fanger in CRC Critical Reviews in Food Technology, July 1971, pp. 245-264]. However, their utilization for the flavouring of dry vegetable materials is hampered for the above given reasons. The present invention provides a simple and efficient solution to the problem of flavouring uniformly comminuted vegetable matter.